Hell Knight

Hellknights are most definitely a force to be reckoned with. They have incredibly powerful projectile attacks, along with staggering power in their claws. Fortunately, they're slow as sin. Keep your distance, and try to fight them in open areas. Though they area slow, you'll have to make sure they don't back you into any corners. Chaingun fire works well if concentrated on the head, and a few up-close shotgun blasts can work wonders, though you'll have to be especially quick when going in for the attack.